Submission #938896

#	Time	Username	Problem	Language	Result	Execution time	Memory
938896		sysia	Boat (APIO16_boat)	C++17	9 / 100	4 ms	604 KiB

boat

//Sylwia Sapkowska
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << "'" << x << "'";}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

#define int long long
typedef pair<int, int> T;
const int oo = 1e18, oo2 = 1e9+7, K = 30;
const int mod = 1e9+7;

int mul(int a, int b){
    return (a*b)%mod;
}

void add(int &a, int b){
    a += b;
    if (a >= mod) a-=mod;
}

int add2(int a, int b){
    a += b;
    if (a >= mod) a-=mod;
    return a;
}

void solve(){
    int n; cin >> n;
    vector<int>a(n+1), b(n+1);
    vector<int>s = {0};
    for (int i = 1; i<=n; i++) {
        cin >> a[i] >> b[i];
        s.emplace_back(a[i]);
        s.emplace_back(b[i]);
        s.emplace_back(a[i]+1);
        s.emplace_back(b[i]-1);
    }
    sort(s.begin(), s.end());
    s.erase(unique(s.begin(), s.end()), s.end());
    debug(s);
    vector<T>seg;
    for (int i = 0; i<(int)s.size(); i++){
        seg.emplace_back(s[i], s[i]);
        if ((i+1) < (int)s.size() && s[i]+1 <= s[i+1]-1) seg.emplace_back(s[i]+1, s[i+1]-1);
    }
    debug(seg);
    int m = (int)seg.size();
    vector<int>dp(m, 0);
    dp[0] = 1;
    for (int i = 1; i<=n; i++){
        auto new_dp = dp;
        vector<int>pref(m);
        pref[0] = dp[0];
        for (int j = 1; j<m; j++) pref[j] = add2(pref[j-1], dp[j]);
        debug(pref);
        for (int j = 1; j<m; j++){
            if (seg[j].first >= a[i] && seg[j].second <= b[i]){
                add(new_dp[j], mul(pref[j-1], (seg[j].second-seg[j].first+1)));
            }
        }
        dp.swap(new_dp);
        debug(i, dp);
    }
    debug(dp);
    int ans = 0;
    for (auto x: dp) add(ans, x);
    ans--;
    if (ans < 0) ans += mod;
    cout << ans << "\n";
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t = 1;
    //cin >> t;
    while (t--) solve();

    return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 0 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42